@Misc{ 
  FarVal12,
  author = { Farina, Alberto and Valdinoci, Enrico },
  title = { On partially and globally overdetermined problems of elliptic type },
  journal = { American Journal of Mathematics },
  year = { 2012 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/2100/ },
  note = { cvgmt preprint}
}